1. Field of the Invention
The invention relates to a device for removably fixing an electronic module to the surface of a tire.
2. Description of Related Art
The use of electronic modules in tires makes possible a wide range of applications including the acquisition, storage and transmission of information in order to track manufacturing or logistics, and more generally informing the user of changes in performance of the tire over the course of its service life.
This electronic module may comprise passive components, such as identification chips or RFID chips, and/or active components connected to an independent system for supplying electrical energy, such as batteries, or indeed an inductive coupling system, which does not form part of the invention. The modules are designed to exchange the desired information with external modules, serving as an interface with the user, by way of radio waves, the frequency and power of which are carefully adjusted to specific transmission protocols. The modules are generally disposed inside flexible or rigid protective casings which are intended to protect the electronic components from shocks and the environment prevailing in and around the tire.
The module, which by way of example is positioned inside the cavity formed by the tire once the tire is mounted on the wheel, may be disposed on a wide variety of supports. Thus, it may be fixed to the valve or to the rim, fixed or glued to the inner wall of the tire cover, or indeed integrated within the components of the tire. The selection of one of these solutions depends on the type of tire and the stresses it must undergo, the type of power source for the electronic module, the information which is to be tracked and the desired accessibility for maintenance.
One of the difficulties to be resolved by those skilled in the art taking on these problems relates to overcoming possible interference between the radio waves and the components of the wheel or the tire. This problem proves particularly difficult to solve if one of these electronic modules is to be disposed inside a tire having metal carcass reinforcement plies.
In this latter case, the solution consists of disposing the module as close as possible to the wall of the tire, while taking into account the flexibility of the tire and the relative rigidity of the module, the resistance to shocks, the possibility of removing the module in order to perform maintenance on it, and the need to ensure that the module is kept in position whatever the speed of rotation and the conditions of use of the cover.
Ways of fixing the module to the tire which allow these requirements to be met are described, for example, in the publication EP 0 936 089 (which corresponds to U.S. Pat. No. 6,030,478), U.S. Pat. No. 6,255,940 or indeed U.S. Pat. No. 6,462,650, which describe systems for fixing a module to the inner wall of a tire. These devices are composed of a flexible sole plate, of which one face serves to provide a connection to the inner wall of the tire and the other face has a fixing means which cooperates with the attachment means disposed on the module.
However, all the solutions proposed in the publications discussed above relate to devices in which the base that serves to provide a connection between the inner wall of the tire and the module proper is relatively bulky and has, in particular, protruding means of connection to the module.
This latter characteristic is particularly inconvenient when the tire has to undergo retreading in the hot condition, since this base and the means of connection to the module associated therewith run the risk of damaging the wall of the curing membranes used for this operation. Added to this inconvenience is the fact that there are local variations in the heat exchange conditions.
It thus becomes necessary to remove this base by grinding it away before the step of vulcanization and, given the destructive nature of the grinding operation, to replace the base after the vulcanization operations are complete.